1992 15 hp Evinrude losing fuel?

[newfiez]

So I just rebuilt a carb and external fuel pump on a 1992 15 hp Evinrude. The engine starts and runs fine, but after a minute or so, the engine will die, unless I pump the gas line bulb. I put a brand new kit in the pump, and the gasket between the pump and head is new. Is it possible that I built it up wrong? I've tried assembling it in the other ways suggested in the parts manual and it runs the same.

 

[bktheking]

Re: 1992 15 hp Evinrude losing fuel?

Go buy a pump, the rebuilds are a PITA and don't anways work. To test you could always pump up the carb bowl, pull the hose going to the carb and put it in a gas can and watch to see if it's pumping while running. Float could also be an issue.

 

[OptsyEagle]

Re: 1992 15 hp Evinrude losing fuel?

There is the blow/suck test for the pump where air should be able to go through the one way and be restricted going the other.

The other area of failure could be your tanks fuel hose. The check valves in the primer bulbs do fail and can restrict fuel. If you can get another hose, you should try it out before you buy another pump. If I recall they wanted over $100 for a new pump on my 1975 motor. A new primer bulb with check valves is only $10.

 

[jmendoza]

Re: 1992 15 hp Evinrude losing fuel?

Check the clamps on all of the fuel lines from the fuel line fitting to the pump, and from the pump to carb are tight, then check the o ring seals on your fule line fittings from the tank to the engine.

 

[newfiez]

Re: 1992 15 hp Evinrude losing fuel?

Check the clamps on all of the fuel lines from the fuel line fitting to the pump, and from the pump to carb are tight, then check the o ring seals on your fule line fittings from the tank to the engine.

Clamps are all tight, this is a new hose that I have rigged with quick disconnect fittings at the end for multiple use with different manufactured engines.

I'll try hooking a clear line up between the pump and the carb to see if it's pumping through at all. I'm not sure, but the pump that's on there may be from a 9.9...but I don't know if that makes a difference.

 

[bktheking]

Re: 1992 15 hp Evinrude losing fuel?

Same pump

 

[OptsyEagle]

Re: 1992 15 hp Evinrude losing fuel?

Unfortuneatly, a clear hose may help you see the problem if it is an air leak but not if it is a restriction. In a restriction, you may find that fuel is in there but once a restriction is experienced the vacuum it creates overpowers the pump and hence the fuel does not move into the carburetor.

Something to think about.

 

[newfiez]

Re: 1992 15 hp Evinrude losing fuel?

Unfortuneatly, a clear hose may help you see the problem if it is an air leak but not if it is a restriction. In a restriction, you may find that fuel is in there but once a restriction is experienced the vacuum it creates overpowers the pump and hence the fuel does not move into the carburetor.

Something to think about.

Where would you suggest that the restriction would be? I'm getting fuel right from the tank to the carb as long as I slightly squeeze the gas bulb when the engine is running.

I installed another pump and it's having the same issue as the pump I rebuilt. The engine runs for a minute, then the carb runs out of fuel (unless I squeeze the gas bulb). So with the engine running, I removed the outlet hose (to the carb) off the pump, and the gas coming out was in small spits...then nothing at all...then as the engine was dieing from fuel starvation, just before it shut down, the fuel pump spit gas out again. Is it possible that the engine has very little or no base pressure? The engine runs fine at all rpm's if I'm squeezing the gas bulb.

 

[bktheking]

Re: 1992 15 hp Evinrude losing fuel?

That pump is driven by motion of the piston, have you checked your compression?

 

[OptsyEagle]

Re: 1992 15 hp Evinrude losing fuel?

Also, squeezing the primer bulb can usually overcome many restrictions such as a non vented tank or a malfunctioning check valve in the fuel hose, etc, however, those same restrictions will prevent the fuel pump from moving the fuel into the carb. By squeezing the bulb you will most likely fill the fuel hoses and carb but once you stop, the fuel will stop moving. Some believe that it runs out of fuel, and in the carb that may be true, but in the fuel hoses, it is not. The vacuum created by the restriction overpowers the pump and the fuel just stays pretty stationary in the hoses and lines, sheding very little light on the situation with a clear hose.

There are many possibilities here. It is possible that you rebuilt the pump wrong. Did you do the blow test to see if air goes through the pump one way and not the other? The other possibilities are tank venting and check valve malfunction in the fuel hose. If you had a different tank and/or fuel hose to try, that would be useful. Of course air leaks are another possibility. Those can be from not tightening the screws on the pump itself tight enough, the fuel hoses and perhaps even the quick connects that you said you retrofited on this unit.

I would agree from what you said and the test you did, that the fuel is not passing the fuel pump properly and this is your problem.

 

[Will Bark]

Re: 1992 15 hp Evinrude losing fuel?

You should check the inlet tube in your tank for restrictios, screen may be clogged, may have a crack in the fitting(mine did); but if all is good then try moving tank up to the same level as the pump, if fuel flows then; you have a weak or leaking pump. As someone pointed out it is best to just replace the pump insted of wasting time and money to rebuild.

 

[bktheking]

Re: 1992 15 hp Evinrude losing fuel?

I guess it was missed in his last reply:

I installed another pump and it's having the same issue as the pump I rebuilt.

2 pumps, same issue

 

[OptsyEagle]

Re: 1992 15 hp Evinrude losing fuel?

I missed it. I think you can rule out the pump then and move on to the other things like the tank, fuel hose, quick connects, etc.

 

[newfiez]

Re: 1992 15 hp Evinrude losing fuel?

You should check the inlet tube in your tank for restrictios, screen may be clogged, may have a crack in the fitting(mine did); but if all is good then try moving tank up to the same level as the pump, if fuel flows then; you have a weak or leaking pump. As someone pointed out it is best to just replace the pump insted of wasting time and money to rebuild.

Ok, I tried putting the tank to top of the engine, and it ran longer, but when I demanded more power, it slowly ran out of fuel. I think it could idle all day long with the tank on top.
The fuel tank I'm using is the same tank I use on all models of engines (which has quick disconnect for each model), and the hose on there for the evinrude, I've used on other engines without any issues. I even tried it on my 8 hp Evinrude, and everything worked fine. So I grabbed a line and tank from my everyday boat, hooked it up, and it now works! So weird that it wouldn't pull from the other tank, but it runs off the other. Thanks guys for your help.....something so simple as a fuel line.

 

[OptsyEagle]

Re: 1992 15 hp Evinrude losing fuel?

Didn't like to keep harping on the tank and fuel hose, but once you determined that fuel wasn't pumping past the pump and it was not the fuel pump itself, there really wasn't much left to look at.

Glad you got her going.